Disk brake with a parking brake, mechanical thrust assembly, and method of assembling

An arrangement comprising:

• a brake piston configured to operate at least one disk brake pad, the brake piston including a front transverse wall having a radial orientation and a lateral cylindrical tubular wall that extends axially towards a rear;
• and
• a nut-and-screw unit for the axial thrusting of the piston, from the rear to a front, the nut-and-screw unit comprising:
• a nut that is disposed in the interior of the piston, the nut being secured to the piston in order to prevent rotation, the nut being mounted in the piston to slide axially, the front axial end face of the nut interacting with an internal section facing the front wall of the piston, in order to push the piston axially towards the front when a screw of the nut-and-screw unit is driven in a rotating manner in a direction of unscrewing, and
• the screw including a front section that is mounted screwed into the nut, an intermediate radial flange delimited by a rear transverse face, and a rear section,
• wherein the piston and the screw include means for centering that includes two centering portions that interact with one another when the screw is in a predetermined front axial mounting position, in relation to the nut and to the piston in order to center the rear section of the screw radially in relation to the piston, the two centering portions including a supplementary front portion of the intermediate flange and a supplementary rear portion of the piston, the rear portion of the piston being disposed at a rear axial transversal extremity face of the lateral wall of the piston,
• the supplementary portions being truncated spheres.

A method of mounting a hydraulic disk brake for an electromechanical parking brake, the method comprising:

• providing the disk brake including a rear housing inside of which is formed a cylindrical cavity that is open axially towards a front, the cavity housing an arrangement including a brake piston mounted to slide in a sealed manner in a bore of the cavity and housing a nut-and-screw unit configured to provide axial thrust of the brake piston, from the rear to a front, the piston and the screw including means for centering that includes two centering portions that interact with one another when the screw is in a predetermined front axial mounting position, in relation to the nut and to the piston in order to center the rear section of the screw radially in relation to the piston, the two centering portions including a supplementary front portion of the intermediate flange and a supplementary rear portion of the piston, the rear portion of the piston being disposed at a rear axial pg,24 transversal extremity face of the lateral wall of the piston, the supplementary portions being truncated cones;
• assembling the brake piston, the nut, and the screw in order to form the arrangement;
• adjusting the axial position of the screw in relation to the nut and to the piston in the axial mounting position to center the rear section of the screw radially in relation to the piston;
• introducing the previously-adjusted arrangement, from the front to the rear, axially into the cavity of the housing;
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• securing the rear section of the screw axially in relation to the housing;
• and unscrewing the screw in relation to the nut.